Apparatus for indicating tilt of cameras



Feb. 24, 1942. F. w. LUTz ETAL APPARATUS FOR INDICATING TIL'JT ,OFCAMERAS 2 Sheets-Sheet l origina; Filed Jan. 8, 1958 INVENTQRS'edelcc/r/ W Luft Jahn D. PeaceJ BY ,9 WQ @M mi, M

Feb. 24., 1942. F, `w- LUTZ ETAL l 2,273,876

APPARATUS FOR INDICATING TILT OF CAMERAS Original Filed Jan. 8, 1938 2`Sheets-Sheet 2 LF INVENTORS Frederic/v Wfuz BY John l). PeacQJr.

memo Fb.24,1942 I .I t' e e I' .APPARATUS FOB INDICATING TILT 0F CAMERASv Ullll'llso STATES rTENT" OFFICE? meel-lex w. nu. om city, ma :ons n.Peace, Jr., Flushing, N. Y.

cgnnnusagmlgappusausn 117m 1113.912, an Thlsapplica n ebruary mwa-m No.:n.424

claims (cios-1.1) i This invention relates to aerial cameras and`auxiliary tothe main'camera or other instru- L has particular referenceto means for indicating, ment; and.

.orregisterlngonthecameranlm.oronanasFigureillustratesanothermodiiicationin sociated record. the relativetilt of theveamem at which a spot of light records on a graduated filmthetimeanexposurewasmade. 5 .therelativetiltofthelnstrument Inaccordance withfthe present invention ,e This application is acontinuation of our oogravity stabilized light projection means is asso-Pending application, Serial No. 183,978. filed Janeiad with a camera orother observation mmuary 8, i938. entitled "Apparatus for indicatingment, and with a graduated scale xed or othertilt 0! m" wise connectedto the camera for indicating on lo Referring to Figure 1 of thedrawings, numeral the scale the relative tilt of the camera or other ldesignates the n1131118 0f D fm m8 0f instrument with respect to thestabilized moons, the Fairchild type, for example, which is suit- Inapreferred embodiment of the invention for ably mounted in the usual wayon a universal use with a camera, the light projected by the Support.not shown. for maintenance of a normeans is preferably photographicallyregistered ls mal vertical position on an aeroplane or other with animage of the associated scale on the mm aerial craft, and which is ttedwith a removable for providingonthe pictureareoord of the rela 111m e Ilhaving the reels l2 between tive tilt of the camera at the time ofexposure. which the film Il is moved over a pressure platePbrusewithanyinstrumengmammrymm ,sothatthelmliesinthefocalplaneofthe maybe utilized to record photographieally the 20 camera lens il. Uponexposure the image of relative tilt of the instrument at the time of anythe selected subject, such as the ground beneath, Particular reading orobservation. Also, the new 1S rejected by the lens upon that Dertien Il0f r tilt indicating and tilt recording means. may be the film I3 lyinglon the pressure plate Il. operated simultaneously, and other modmeeuomPreferably formed 1 in or directly associated of the tilt indicating orrecording means may be with the camera housing Il is a chamber il,beprovided in accordance with nous requiretween the opposite walls Iland Il of which is ments. mounted the gimbal .support 2l of a small ver-I'or amore complete understanding of the mtical axis gyroscope 2| in themanner illustrated vention,referencemgybehadtotheeeeomm inFigureslandZ.Gyroscopellmaybeeither ingdrawinglinwhich, 30 of the.electrically-driven or air-sustained rotorFigurelisaverticalsectionthroughamoretype,dependinguponcircumstancesandrequire 'orless conventional form ofaerial eameraiitted men mempepmeredfitwbe with ons form of the tutreeoramgapparann or Mmm *het Other mible elements. wh esingsealeasseenalongthelinel-Iofi'igurel;

this invention; Y peggculum, used wiplhrtequal of Figure 2 is anenlarged horizontal geen@ 35 ured upper o casing therethrough, es eeendem the in 2 2 o! gyroscope 2| for relative movement therewith,is

mun v .afxamellcai'ryingascreenllhavingiinapel'-nguresisanenlareedviewoxmemnnmoatim I* "m mmmne'nmum thevgticalaxisoithedgyroscope 2|. Theaper- Flmlspomgnofmpednmmm lllyb anyeil'edlhpiuchllthe hvingphotographedthereonthetiltreoord:crossilltratedinl'isiu'e2.whichisasectlonHguretisafragmentaryverticalsectionofa ne hummel-'2 Ml'figm'el. Thewwwmumnmthemem screenttorreticule formed therebisecnvexYparatus'mountedonacameraorotherimia-u- 'mitmm-ofmmhtmmm ment for directobservation of the degree of'tilt A dptdmmpe" mi; tionedbehindereticuleorscreenu mciuonoxwmcnabotnmanueabrwe vangemessene mun'enmytmted eameraanddirectlyehrvedinihemmder: hy'orsimultanehemywitntli'edcawamutter zl'igurelisafragmentaryverticalsectionmmeehemmnthetmemmm; ihroughamodiiicationinwhichasepu'atetiitnatedonlywhmtheiilmltiselped.- .Y reoordingapparatus with itsseparateiilmisll lloimtedoverthereticuleorsoreenonthe frame of thecamera for movement therewith is a transparent or translucent scale 2l,illustrated in detail in Figure 3, and so positioned that its centerlies exactly on the vertical axis of the gyroscope 2| when the camera islevel, so that the center of the aperture 24 of screen 23 and the centerof the scale 28 coincide as is indicated in Figure 3. The scale 28 iscalibrated at 29 in degrees of tilt in coordinate vertical planescoincident with the vertical planes of the arms of the reticule cross24, so that the position of the reticule cross 24 indicates the angle aswell as the direction of tilt of the camera. The scale is alsosubdivided into squares 3|! about the center point for aiding inmeasuring tilt in directions other than along the planes of thegraduations 28.

The curvature of the scale 28 conforms to that of reticule or screen 23,and where the latter is opaque, the scale 28 is spaced slightlytherefrom so as to be suiiiciently illuminated that its image is clearfrom above. Where the reticule or screen 23 is translucent, it may bemore closely positioned to scale 28. The arrangement must be such thatwhen viewed from above, both the scale 28 inscriptions and the reticulecross 24 must be clearly outlined and sharply identifiable for accuratereading. Alternatively the screen 23 may be transparent or translucentand the cross 24 may be opaque, providing a sharp outline of the latteron the scale 28.

The beam of light issuing from the reticule or screen aperture 24 andpassing through scale 28 is reiected by 45 plane reflector 3| laterallythrough fixed lens 32 upon another 45 plane reeotor 33 which in turnreflects it upon a portion of the iilrn I6 lying outside of the field ofview of the camera, being screened therefrom by wall 34. The image ofthe scale 28, with the reticule cross 24 superimposed thereon, isaccordingly photographed on the illm adjacent to the picture and becomesa. part of the negative, as is indicated at 35 in Figure 4. By means ofrecord 35, the degree of tilt of the camera at the instant of exposureis indicated on the negative itself and correction for tilt can beimmediately and accurately made.

In the arrangement of Figure 5, the tilt indicating apparatus is mountedon an instrument, such as the camera I0, and the degree of tilt isobserved directly on the scale 28, the Syroscope 2| carrying thereticule or apertured screen 23 as before, but the lamp 25 is providedwith a lens 3i for directing parallel rays through the reticule upon theunder side of the scale 28, the

image of the reticule being visible through the transparent ortranslucent scale 28 in the manner described.

In Figure 6 there is shown a combination of the arrangements of Figures1 and 5, in that thedegreeoftiltisbothrecordedonthenlm ofthecamerallinthemannerdescribedmd is directly indicated in the view nndertelescope 31 mounted on the camera Il. The tilt recordisphotographedonthefilm |3bymeansofthe stabilized optical system,including the gymscope 2|, lamp 2l, reticule or aperhired screen 23,scale 28,reilector 3|, lens 32 and reector 33, as described inconnection with Figure l. At thesame time theobservermaylevelthe'camembefore exposure by reference to the tilt indication in the view nder 31,which is provided by a duplicate stabilized opdcal system. Thissystemisoonnectedtothelowerendotthecnsing of gyroscope 2| and includes areticule or apertured screen v23' carried by the gyroscope 2| andidentical to screen 23, the iixed scale 28' identical to scale 28,reiiector 3|', lens 32' and halfsilvered reflector mirror 38 in the eldof view of the telescope 31. The image of the scale 28' withsuper-imposed screen 23 aperture is clearly visible on reflector 38without obstructing the view of the telescope 31, since thc reflector 3lis largely transparent. Instead of being energized only when an exposureis made as in the case of lamp 25, the lamp 25' is constantlyilluminated so that observation of the degree of tilt may be made at anytime, such as before a picture is taken.

In the arrangement of Figure 7, the tilt recording apparatus is separatefrom the camera, being an auxiliary unit 4|) attached to the housing ofthe main camera I8, and having its own film 4| on which is recorded thetilt indication. The stabilized optical system, including the lamp 25,energized simultaneously with the camera shutter, the reticule orapertured screen 23 and the scale 28, is the same as in Figure 1, andwith it the image of the scale 28 with superimposed reticule is formedon the auxiliary iilm 4| by lens 42. The auxiliary recording iilm 4l isadvanced at the same time and at the same relative rate as the maincamera film I3, the reel 43 of the recording film 4| being driven byconnections 44 from within the camera I0 by the mechanism which advancesthe main iilm I3. I'he `corresponding length of auxiliary film 4| andmain lm |3 bear like cross-reference characters or numerals 45 so thateach exposure of the main iilm |3 may be checked for tilt by referenceto the corresponding length of recording fllm 4|.

In the arrangement of Figure 8, which is a modification of the auxiliaryrecording mechanism of Figure 7, the gyroscope 2| is not iitted with thescreen or reticule, but merely with a center reflector 46 under a lens41, while the lamp 48, provided with a hood 43, directs a beam of lightupon a 45 half-silvered reilector 58, which reflects the light into themirror 46 for direction by the lens upon the auxiliary record illm 4|'positioned in the focal plane of the lens 41. The record nlm 4| isprovided with longitudinal parallel graduations 5| at either side of thecenter line 52 representing the degree of tilt of the instrument in oneplane, i. e., when the instrument is level, the image of the light spotfrom lens 41 falls on the center line. Cros graduations 58 indicate thedegree of tilt of the instrument in the other plane.

Itwillbeseenthattheamaratusofthisinvention provides a very simple buteiIective means for indicating, or registering a permanent record of thedegree o! tilt of an observation instrument or the like at the time thatan observationismadaand thattbeinventionispeculiarlyldvantageoustoaerialcamerasaltbwghnotlimitedtothatuse.Itisalsotobeunderstoodthat, while certain preferred embodiments of theinventionhavebeenillustntedanddescrlbedherein.theinventionisnotlimltedthereby,butissusceptible ot change in form snddetailwithmthescopeoftheappendedclshns. Pbrexsmple,thereticuleorotherindicatormaybenedonthecameraandthescaleconnectedtothegyrosoopemdanauxiliaryiilmmnybelssodatedwith an observation instrument other than s camera, and the like.

Thetermillmasledhereinandinrtnin oftheappended cialmseomprehmdsallformsof photo-sensitive films however applied, whether determine the attitudethereof preliminary to on a plate, nexible cellulose derivative thelike.

We claim:

1. A device for indicating the tilt of an aerial camera and forrecording the amount oi' tilt on a nlm, said device comprisins. incombination, a stable element movably mounted on said camera, a viewnnder mounted on said camera, a plurality ofmembers connected to saidelement and movable therewith, whereby said members remain inpredetermined positions regardless oi' the attitude of the camera at theinstant of exposure of said nlm, an optical system mounted on saidcamera and optically arranged relative to one of said members and tosaid nlm for projecting an image of said one member on said nlm at thestrip, or

' instant of exposure -so that the nlm when developed will include arecord of the attitude oi the camera at the instant of exposure, and anopti-A cal system mounted on said camera and optically arranged relativeto anotherof said members and to said view nnder for projecting ,animage of said other member within the neld of view of said view nnder sothat the operator of the camera can determine the attitude thereofpreliminary to taking an exposure.

2. A device for indicating the tilt ot an aerial camera and forrecordingthe amount of tilt on a nlm, said device comprising, incombination, a stable element movablyy mounted on said cam- Y era, aview nnder mounted onsaid camera, a pair of tilt measuringmembersonsaidcamera.-

a pair of apertured munbers on said camera,meansadaptedtoconnectsaidnrstpairoimemlberstosaidcameraandtheotherpaiiotsaidlmembers to said stable element, whereby one member of each pairismovable relative to one memberoi theotherpair,twosourcesoflightin saidcamera, one light source being arranged adjacent one tilt measuringmember and one apertured member, and the other light source beingarranged adjacent the other tilt measuring member and apertured. member,one light source, one tilt member and one apertured membercomprising aprojecting unit whereby all of said members and light sources form twoseparate projecting imita, and mans including a view.

nnder and an optical system mounted on said .camera andopticailyarranged relative to one oi said unitsandtosaidnlmiortransmitting the` projection from said last-mentioned unito! the makingan exposure. l Y

3. A device for indicating the tilt oi an aerial camera and forrecording the amount of tilt on a nlm. said device comprising, incombination, a stable element movably mounted on said camera. a viewnnder mounted on said camera, a pair of reticules connected to saidelement in alignment with the vertical axis thereof, whereby saidreticules remain in predetermined positions regardless of the attitudeof the camera at the instant oi exposure of said nlm, a scale memberconnected to said camera closely adjacent each oi said reticules wherebythere is provided a reticule and a scale member on each side of thehorizontal axis of said stable member, means for illuminating saidreticules, an optical system mounted on said camera and operativelyarranged relative to one of said scale members and to said nlm forprojecting an image of at least a portion of saidv one scale member onsaid nlm at the instant of exposure so that the nlm when developed willinclude a record of the attitude of the camera at the instant ofexposure, and another optical system mounted on said camera and arrangedrelative to the other of saidl scale members and to said view nnder i'orprojecting an image of at least a portion of said last-mentioned scalemember within the neld of vision of said view nnder so that the operatorof the camera can determine the attitude-thereof preliminary to makingan exposure. l

- 4. An aerial camera comprising, in combination. a casing, a nlmcompartment in said casing adapted to receive/r roll o! nlm or the like,means iormingachamberinsaidcasing,agyroscope mounted in said chamber formovement relative -tosaidcasing.tiltmeasuringmeans lncludinga image otone ofthe members in said last-mentioned unit within-.the neld or viewci' said view nnder sc that the operator oi' the camera can source ofillumination and an optical system for.

Projecting on said nlm an indication of the inclination oi' said casingrelative to the attitude of said at ythe time of exposure, a view nnderconnected to said casing and including an optical system, second tiltmeasuring' means in said casing and including a source oi illuminationand an optical system for projecting an indication of theinclination ci,said casing with respect to the .attitude ot said gyroscope, saidlast-mentioned optical system being operatively associated with at leasta portion of the optical system in said view nnder whereby the operatorof the camera can determine the attitude thereof preliminary to makingan exposure.

FREDERICK W. LU'I'L. JOHN D. PEACE, Ja.

